Resonators, i.e. systems that are able to oscillate, exist in many variants. By way of example, resonators can be embodied as RF cavities, in which electromagnetic oscillations can be excited. The use of such RF cavities in particle accelerators for accelerating electrically charged particles is known.
In order to excite and maintain a resonator oscillation, energy must be supplied to the resonator from an external source by means of an excitation device. To this end, radiofrequency sources are used in resonators, embodied as RF cavities, of particle accelerators. It is conventional to regulate an output amplitude of these radiofrequency sources in order to regulate the amount of energy fed into the resonator. However, when using solid-state switches for the excitation in particular, this ability to modulate the amplitude requires significant outlay and reduces the efficiency of the known excitation devices.